CAPP –Computer Aided Process Planning Overview
(Author: N. Mohan Raj, Chennai)
This White paper explains briefly on the standard value calculation via CAPP. Basically, CAPP is one of the master data element in Production planning module.
Main objective of the document is to explain the basic concept of CAPP with Business examples as well as sap Process flow. Best attempt has been made to explain key settings, advantages, Disadvantages & Limitations of CAPP. I would also update versions based on feedback and comments of SDN experts and consultants on this topic accordingly in future.
CAPP can be carried out for Discrete Manufacturing or PP-PI or REM. However this document limits to Discrete Manufacturing only.
Applies to: ECC 6.0, Sap R/3 4.6
Need for Computer Aided Process Planning:
Standard values are used in scheduling, capacity planning and costing to determine dates, capacity requirements and costs. Standard values can be determined in several ways:
- · conventional procedure for determining times (for example, time studies, estimating, polling)
- · sampling and statistical procedures for determining times (for example, period time sheets)
- · calculation methods (for example, MTM, WF and planned times)
In contrast to the procedures listed above, CAPP is a mathematical procedure using formulas and methods.
Structure of standard value calculation via CAPP follows below sequence
Work center (Tech data) >>>> Processes >>>>Methods >>>>Formula
Basics of CAPP elements:
Characteristics and tables serve as the basis for calculating standard values with CAPP. They are used in CAPP elements.
- A characteristic describes any detail or feature of an object, such as the length of a screw or the depth of a casing. Characteristics are used in formulas for calculating standard values. They are also used in classification.
- Data in tables can be used calculating standard values. Tables consist of key fields (for example, plant and work center) and one or more values in the function section of the table, which refer to the key fields. Tables are classified as General Tables, Table for Work center, Matrix Table and Database Table.
Note: This document covers only characteristic based calculation for ease understanding purpose.
Let us take a simple Business scenario in a company. For a new product, company has commissioned a new drilling machine (work center). So Product routing will have drilling operation which will be carried out in the new drilling machine. Company requested to do standard value calculation via CAPP method for setup and Machining and also needs to be updated in Routing using Engineering formula.
Calculation sample from Engineering:
1. Setup time = Basic time + ( Number of Tools * variable time ) with 10% Excess factor
So Final setup time formula = (Basic time + (Number of tools *variable time)) * 1.1
Ex: Set up time = (10 + (2 *5)) * 1.1 = 22 min
2. Machining time = ( Number of drillings * Drill depth )/ drill speed
Ex: Machining Time = (6 * 4) / 8 = 3 min
Let us do standard value calculation via CAPP method
Sap Process Flow of CAPP:
A.1 Work center Setting:
Production –> Basic data –> work center –> setup work center sequence
Activate Technical data tab for work center category say 0001
A.2 CAPP specific Setting:
Production –> Basic data –> capp –> Define sort string, value type, machine type, planner group, control parameters
Purpose: CAPP specific configuration
a.Sortstring & Machine Type ( Information purpose only ) :
b.Value Type ( Mapping of value type to Standard value parameter – Important one ) :
c.Planner group :
d.Control Parameter ( Defining increment and calculation Type ) :
- All formula characteristics must be predefined in CT04
- Unit and decimal, format has to be taken care.
1. CAPP Formula (Tcode: CE11):
Create Engineering Formula as per requirement for both setup & Machining. Refer below
Set up – CAPPTEST; Machining – CAPPMACH
Example : Formula – capptest ,status – 1 (active )
Formula ( 3 lines will be there )
(Basic time + (Tools * var time )) * 1.1 .
Please note Basic time , tools , var time are defined as char already .
2. Method (Tcode: CE21)
Create a calculation method to link Formula and valuation type configured.
· capptest method will have CAPPTEST formula & cappmach method will have its formula
· Keep method status as active (1)
3. Processes (Tcode: CE31):
Now create process which will link method or methods.
- · Each process has allocated with method ( CAPPTEST PROCESS >>>CAPPTEST METHOD )
- · Also , activate process status to 1
4. Work center – Technology view (CR01 / CR02)
- · Create or Update work center (CAPP01) with Technical data in Technology tab
- · Additional values or rounding is not mandatory
- · No of Processes must be minimum 1. For initial setup , assign process as defined below
After assignment of processes , click consistency check. There should not be any error .
5. Routing (Tcode: CA01)
· Now create routing for the material and assign above work center CAPP01
Execution of Capp :
CAPP execution has to be done step by step as below
2. CAPP calculation – Routing & Updation
3. Production order or planned order creation with CAPP calculation
Let us illustrate steps in details
Main Purpose of simulation is to verify and validate CAPP formula, method, process and its calculation are correct and in sync.
This is to ensure standard value calculation for either machine time or setup time or any time is being done @ work center as per engineering calculation
Enter plant , work center ,process & method for simulation
Enter dummy or trial values in the fields and click next screen
Result of simulation will be populated and click next screen
Final sub calculation is shown below
Note: same can be repeated for other formula
2. CAPP calculation – Routing & Updation:
Change routing: select operation and click Extras –> capp à manual selection
System will show processes assigned to work center. Select all processes and click next screen
Enter expected values for calculation and click to next screen till end
Repeat for another formula also
Finally, you will get message “Last selected process xxxx has been completed “and save it as below
Now check operation in routing where you find values of setup and machine updated automatically .
Also , you can note calculation type and year calculated is also updated for Referance under “determination of std values”
3. Production order or planned order creation with CAPP calculation:
Scenario 1: No Link to Production order:
If you don’t want to recalculate standard values again during production order creation, keep capp order as blank in Routing header. In simple words, standard values available in routing operation will be retained in production order
Create production order
Check standard values Tab in operation. CAPP values in Routing is copied without any change
Scenario 2: Link to Production order:
If in case you want to change standard values while creating production order due to any reason , then link between routing to production order has to be established . This means, when order is created, system will propose standard values with fields for user to change and save new value in order
Master data setup for linkage – change Routing header > CAPP ORDER Field as 2 as below
Now create production order via co01, system will pop up screen with current standard values.
Let user change values as below
Number of drillings from 8 to 10, depth from 5 to 6
Go to next screen, system proposes result based on new values as below
Same can be done for another formula also with new values if needed .
Final summary of result is shown.
1. Refer system status – CAPP which means std values calculated via CAPP
Check Standard values in operation which shows new calculated values
*** CAPP calculation which is carried out for the order above will not change routing master values.
This concludes the complete cycle of CAPP scenario in PP.
Key Points summary:
- CAPP calculation of standard values can be done for Routing or Ref operation set
- Standard values calculation can be done automatically if process & method marked standard indicator.
- Capp calculation can be done for variant configuration also for operation
- If SVK is missing in work center , standard values calculation cannot be carried out
- Sub operation standard values can also be calculated.
- You cannot calculate value types for standard values if it was specified in the work center that they must not or should not be entered
- If the base quantity of the operation deviates from that of the method, then the method result calculated is converted to the base quantity of the operation during a standard value calculation.
In General, CAPP is an excellent method for calculating standard values of each work center during initial setup of production line. This CAPP tool can be used for initial simulation & freezing final value by trial and Error. Computer-aided process planning is a link between design and manufacturing in a computer-integrated manufacturing environment. Commonly used by manufacturing engineers, CAPP can be used to develop a product manufacturing plan based on projected variables such as cost, lead times, equipment availability, production volumes, potential material substitution routings and testing requirements.
However, usage of CAPP tool in sap looks very limited or might be not explored by customer in big way …. Still reason is unknown!!!